Environment Variables¶

Required¶

UNREAL_ENGINE_PATH

Required on Linux. Your Unreal Engine installation directory — the folder containing Engine.

On macOS and Windows, Tempo finds Unreal automatically via your .uproject file; setting this overrides that. Useful when you have several engine versions installed.

Build behavior¶

TEMPO_GEN_RUST_API

Set to 1 to generate the Rust client crate alongside the Python package. Off by default, since the Rust toolchain is not bundled with Unreal — you need cargo and rustc from rustup.

Rust client

TEMPO_GEN_CPP_API

Set to 1 to generate the C++ client library — headers under TempoCore/Content/Cpp/API/include/ and a static archive under lib/<Platform>/.

C++ client

Testing¶

These are read by Scripts/TestPythonAPI.sh and Scripts/TestRustAPI.sh.

Variable	Effect
`TEMPO_PACKAGED_DIR`	Where to find the packaged build. Defaults to `Packaged`.
`TEMPO_PACKAGED_BINARY`	The packaged launcher to run. Set by the scripts from `TEMPO_PACKAGED_DIR`.
`TEMPO_SERVER_PORT`	Port the test sim listens on, and the client connects to.
`TEMPO_PYTHON_TESTS_DIR`	Which pytest directory to run. Point it at your own project's tests.
`TEMPO_TEST_REPORT_DIR`	Where JUnit and cargo logs are written.
`TEMPO_SIM_RENDER`	Set to `1` to allow render-dependent (GPU) tests to run.

Testing

Command-line alternatives¶

Some settings can also be given on the command line to the Editor or a packaged binary, which takes precedence over project settings until project settings are modified during an Editor session:

UnrealEditor -ServerPort=10002
MyGame.sh -ServerPort=10002

Headless operation for CI:

MyGame.sh -nullrhi -unattended -ServerPort=10001